RMI tach troubleshoot

Has anyone had trouble with their RMI displaying tach values? Everything else on my micromonitor is functioning properly except the tach. It just shows a big fat zero. I checked that I have it wired properly, including the required capacitors, and that the connector was inserting into/onto the tab at the back of the unit firmly. Went so far as to shim the connector off the back of the instrument tray. No joy.


Any suggestions before I give Ron a call?

Regards,

My schematics are in the hangar, but there are a couple of options on the RMI motherboard that need to be selected.

If you look at the schematic, you'll see them illustrated. Check on the motherboard to see if it's set up correctly for the magneto interface.

Vern Little
9A

Thanks Vern. I'll check into that.

Regards,

RMI tach signal

Jeff-

A lot of the electronic instruments need a pull-up (or down) resistor. See here for an example. I had to do this for a couple of circuits to make them behave on my setup.

James Freeman

Hey Jeff


I had a lot of issues with my RMI tach, but Ron eventually helped me out. I have an IO-360-A3B6D, which means I have both mags in a single mag housing (why Mooney wanted this, I'll never know). I always either read 0, or a random tach reading. Anyway, in the end, I had to remove the two capacitors that are inline between the switch and the RMI unit, and replace them with a 10k resitor. That fixed it. I had tried a 1K resistor, but that brought my mags near ground.

Before doing anything like this, check with Ron. He is great for helping out and service.

Cheers

Thanks Mark. I plan to call Ron Tomorrow. I looked into the option that Vern mentioned in the construction manual. That was for setting up the tach for using a Hall effect device, which I am not using. I just have an 0320-E2D on mags, so there must be something that I screwed up somewhere.

Like that has ever happend!